quite often the total memory usage tht my task manager shows is greater than the sum of memory used by all the process it shows..is it normal ??

Where are you viewing the usage? The CPU usage at the bottom of the window?

What is the System Idle Process? This should be the inverse of the CPU Usage.

e.g. CPU=10% | System Idle=90%

no no i was talking about the commit charge it shows in bottom right corner of the task manager ..something like this ...188M/1227M..
wht i meant was tht at times when this usage is about 180 - 210..
the some of memory used by the process's comes out to be lower than this...

Those #'s coincide pretty much with my own.

Is your page file set to System Manage Size?

Here are some other ideas:

http://groups.google.com/groups?q=co...r=&sa=N&tab=wg